Intermittent switching means with pilot light



April 6, 1954 M. KLEBANOFF EIAL 2,674,730

INTERMITTENT SWITCHING MEANS WITH PILOT LIGHT Filed Dec. 15, 1951 INVENTOR.

Jlazmes/l/fickmazz PM]? $1 726)? Y J [z'cimeZ Jf/ebazzoff fi W A'TTORNEY Patented Apr. 6, 1954 UNITED STATES PATENT OFFICE INTERMITTENT SWITCHING MEANS WITH PILOT LIGHT Glickman Application December 15, 1951, Serial No. 261,809

12 Claims.

This invention relates to electric switches and more particularly to switches of the flasher type.

Flasher switches are known in the art which include a .combination of an electromagnet and a thermoresponsive wire as means for alternately opening and closing an electric circuit. Such switches have a working life and operating em,- ciency which in a large part is dependent on the rapidity with which the circuit is opened. 'Accordingly, an object of this invention is to provide an improved flasher switch of the type described, in which the magnet and wire are related in a manner to provide a break in the flasher operation of maximum rapidity.

A further object of this invention is to provide an improved flasher switch of the character described wherein the wire is movable independently of the magnet whereby to accelerate the break in the flasher operation.

Still another object of this invention is to provide an improved flasher switch of the character described wherein the electromagnet carries very little or no current during the break portion of the flasher operation.

Still a further object of this invention is to provide an improved flasher switch of the character described wherein switch contacts are located on members capable of independent movement and arranged to move toward each other during the make portion of the flasher operation and to move away from each other with accelerated speed during the break portion of the device.

Yet another object of this invention is to provide in a device of the character described, improved means for regulating the extent of the make and break portions of switch operation.

Yet a further object of this invention is to. provide an improved combination offlasher switch, load and pilot light, wherein the pilot light in dicates the working condition of the load in an improved manner.

Other objects of this invention will in part be obvious and in part hereinafter pointed out.

The invention accordingly consists in the combination of elements, arrangement of parts and circuit connections which will be exemplified in the embodiments hereinafter described, and of which the scope of invention will be indicated in the claims following.

In the drawing:

Fig. 11 is a diagrammatic view of a flasher switch embodying the invention and the electrical connections thereof;

Fig. 2- vshows the relative location of partsot 2 the device shown in Fig. 1, at the make portion of switch operation;

Fig. 3 is a diagrammatic view similar to that of Fig. 1, showing a modified arrangement of connections; and

Fig. 4 is a diagrammatic view of a device embodying the invention, arranged for operation with a pilot light.

Referring in detail to the drawing and particularly to Fig. 1, li] designates a flasher switch embodying the invention. The same comprises an electromagnet generally designated at H which may be suitably mounted in insulated relation to a base B. The electromagnet I I includes a core [2 having a lateral projection I3, and a winding I4 on the core. The magnet armature I5 is mounted on a resilient spring member l5a which is anchored to base B.

An angle shaped member 16 of resilient, springy metal is anchored at the lower end of its vertical portionto base B and carries a switch contact I! on its horizontal arm portion. A switch contact I8 is mounted on armature [5, in opposed relation to contact 11. Armature I5 is biased, by means of member I5a, away from the core 1,2, as indicated by the arrow in Fig. 1. Member I6 is biased toward armature L5, as indicated by the arrow in Fig. 1.

The contacts l1, l8 are normally maintained in separated or spaced relation by means of a thermoresponsive, resistance wire l9 which is attached at one end to the upper portion of member l6 and is tensioned and anchored at its other end to b se 13.

The switch It) may be connected in circuit with a load L, such as a lamp or t e like, a current source C and a switch 5, as shown in Fig. 1, with the object of flashing the load L as long as switch S is closed. Thus, one end of the winding 14 is connected to the armature 5 and the other end of the winding is connected to one side of the load L and to the wire IS. The member I6 is connected to one side of the current source C through switch S, the other side of the current source being connected to the other side of load L.

A stop screw 20 ounted in a bracket 2| whi h is positioned on base B, provides means for adjustably setting the normal position of the armature 1.5.

When switch S is .closed, current passes through member 16, wire I9 to load L. Since the wire has a relatively high resistance, the current passing through the load is of nominal value and insufiicient to fully. energize the same. However, such current will cause the-wire It to heat up and 3 elongate as indicated in dotted lines in Fig. 1. This will allow biased member It to progressively move toward the armature I5 until contact II engages contact I8.

When the contacts II, I8 engage, a circuit is set up having a resistance much less than that of wire I9 and the wire is shunted. Current will now pass through member I6, contacts II, I8, armature I5, winding I4 to load L. As winding I4 is energized, the armature is moved to its attracted position against its bias as shown in Fig. 2. This in turn causes contact I8 to press against contact H with a force sufiicient to move member I6 against its bias, as indicated by the arrow in dotted lines in Fig. 2 Thus the contacts ll, I8 are positively locked together.

The full value of current from source C will pass through the circuit shunting wire I9, and load L will be fully energized, which in the case of lamps, the same will be illuminated.

With wire l9 shunted and practically no current passing therethrough, the same begins to cool and to progressively contract. This gives rise to progressively increasing tensioning forces in the wire until the value thereof exceeds the biasing force which has moved the member I5 toward the armature I5. At such point, the member I6 is pulled away from armature I5 whose position is fixed by the arm I3 of magnet core I2. Such movement of member I5 is in opposition to the direction of its bias and contact I1 is caused to move away from contact l8.

When contacts II, I8 begin to separate, the shunting circuit is disrupted and the magnet II is deenergized. The armature I5 snaps back to its normal position as determined by the stop screw 20 under the impetus of its bias, thus accelerating the break at contacts II, I8.

As soon as the contacts II, I8 are separated, the current from source C again flows through wire I9, thereby reducing the current flow through load L to a nominal value and the wire starts to heat up again, thus repeating the cycle of operations described above, until switch S is opened.

It is apparent that contacts I'I, I8 are mounted respectively on independently movable members which are adapted to move away from each other with great speed at the break portion of the flasher cycle. Furthermore, when the winding I4 is energized as soon as contacts I1, I8 engage, the movement of the members is toward each other, thereby locking the engaged contacts so as to insure a positive make in the flasher cycle.

The timing of the make and break portions of the flasher cycle, may be adjusted by th stop screw 20. By turning the screw 20 in the proper direction, the normal spacing between contacts II, I8 may be varied. Such spacing determines the extent of elongation of wire I9 required before the contacts engage, as well as the time interval for contraction of the wire sufficient to initiate separation of the contacts.

The flasher switch I may be used in an alternative circuit as shown in Fig. 3. Here, the member I6 is connected to one end of winding I4, the other end thereof being connected to one side of load L. The anchored, or non-tensioned end of wire I9 is connected to armature I and to the other side of load L through switch S and current source C.

With such connections, the operation of flasherswitch I0 is the same as previously described,- except that the winding I4 carrie'scurrent when:

contacts H, II! are separated. However, such current is of negligible value due to the relatively high resistance of wire I9. When current initially flows through wire IS, the same heats up and elongates to allow the contacts to engage, thus shunting the wire I9, as described above. With wire I9 shunted, substantially full current from source C passes through winding I4 by way of armature I5, contacts I1, I8, and member I6, thus energizing th magnet II and causing the armature to be pulled to its attracted position and locking the engaged contacts, as described above. With a very small current passing through winding I4 when separation of the contacts is initiated, the armature I5 moves away from member I6 with accelerated speed,

i thus providing an extremely rapid break in the flasher cycle, as previously described.

The flasher switch embodying the invention may be slightly modified to allow the same to be used in a circuit including pilot means i or indicat: ing the operating condition 'of the load, asshown in Fig. 4. Here, the switch IIIa is similar to that shown in Fig. 1, except that a second pair oi switch contacts 22, 23 are respectively mounted on the armature I5 and arm I3 of the magnet core I2.

The circuit connections shown in Fig. 4 are similar to those of Fig. 1, except that pilot indicating means P, which may take the form of a lamp; is connected between the magnet core I2 and one side of the current source C. The load may take the form of a pair of parallel connected lamps L1 and L2.

When contacts I1, I8 engage, due to elongation of wire I9, as previously described, magnet II will be energized causing contacts22, 23 to engage and allowing current to energize pilot P. However, if either of loads L1 or L2, or both, become inoperative, the current passing through the shunting circuit including winding I4, will be considerably reduced. The bias on armature I5 through spring member I5a is such as to'be insufiicient to prevent full attraction of th arma ture, providing maximum current flows in the shuntingcircuit, but is sufficient to prevent movement of the armature to its fully attracted p051 tion, if the current in said circuit is reduced.

Thus, with reduced current in the shunting circuit, due to failure of one or more of the loads, contacts 22, 23' will not engage and pilot P will remain deenergized to indicate a failure in one or more of the loads. It is understood that the pilot P may take other forms, such as a bell or the like, which may be energized to give perceptible indication of the operating con dition of the loads.

It will thus be seen that there is -provid'ed electric switches in which theseveral objects of" this invention are achieved and which are well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above described invention, and as various changes might be made in the em'bcidi ments set forth, it is understood that all matter herein set forth or shown in the accompanying drawing, is to be interpreted as illustrative and not in a limiting sense.

Having thus described the invention, we claim" as new and desire to protect by Letters Patent? 1. A flasher switch comprising a'pair of members respectively anchored at one end .thereof and including movable portions at'the other *ends thereof, a pair of electrical circuits, one of said circuits comprising a pair of contacts respectively "for TL mounted on the movable portions of said members, the other of said circuits comprising'a thermoresponsive resistance wire attached at one end thereof to one of said members and anchored at the other end thereof andoperative when cool to keep said contacts separated and further operative when heated in response to the passage of a current therethrough, to expand and allow said contacts to engage whereby said second circuit is shunted, said resistance wire upon cooling being operative to contract to initiate the separation of said contacts, the other of said members being movable in a direction to accelerate the separation of said contacts.

2. A flasher switch comprising a base, a pair of members mounted on said base and having free portions resiliently biased in the same direction, a pair of opposed contacts mounted respectively on said members, a tensioned thermoresponsive resistance wire connecting. said base and one of said members for maintaining said contacts in spaced relation, said wire being responsive to the passage of a current therethrough to expand and allow said contacts to engage, a low resistance circuit including said contacts adapted to be energized by said current and thereby shunting said wire, and means for adjusting the normal position of the other of said members whereby to determine the spacing of said contacts. 1 r

, 3. A flasher switch comprising a base, an elec tromagnet on said base and including a magnet winding and an armature resiliently biased in a given direction, a resilient member on said base and biased in the same direction, a pair of opposed, normally separated contacts mounted respectively on said armature and said member, a thermoresponsive wire anchored at one end and attached at the other end thereof to said member and tensioned to maintain said contacts in spaced relation, an electrical circuit including said wire for causing elongation thereof upon passage of current through said circuit whereby said contacts engage and shunt said circuit, a second electrical circuit including said contacts and said winding whereby said winding is energized thereby causing said armature to move against the bias thereof and to lock the engaged contacts, said shunted wire being adapted to cool and contract until said contacts start to separate and deenergize said second circuit, whereby said armature moves in a direction to accelerate the separation of said contacts.

4. A flasher switch as in claim 3, wherein said first mentioned circuit includes said resilient member.

5. A flasher switch comprising a base, an electromagnet on said base and including a magnet winding and an armature resiliently biased away from its attracted position, a resilient member anchored at one end thereof to said base, a pair of opposed contacts mounted respectively on said armature and the other end of said member, a thermoresponsive member connecting said member and base and tensioned to maintain said contacts in spaced relation, an electrical circuit including said wire and adapted upon passage of current therethrough, to cause said wire to elongate and said contacts to engage, said circuit being shunted upon engagement of said contacts, a second electrical circuit including said contacts, armature and winding adapted upon passage of said current to move said armature to its attracted position thereby locking said engaged contacts, said wire in its shunted condition contracting until said contacts startto separate thereby deenergizing said second circuit, the separation of said contacts being, accelerated by the biased movement of said armature from its, attracted position. I 6. A flasher switch comprising an electromagnet including a magnet windingand an armature biased away from its attracted position, a resilient member anchored at one end thereof, a; pair of opposed contacts mounted respectively on said armature and said member, -a thermoresponsive resistance wire anchored at one end thereof and attached at the other end thereof to said memher and tensioned to space said contacts, a first circuit including said wire, a second circuit including said contacts, armature and winding serially connected, said wire being adapted'to elongate upon passage of current through said first circuit and to cause said contacts to engage, said wire being shunted upon engagement of said contacts, said armature being moved to its attracted position upon passage of current through said second circuit, to lock said engaged contacts,v

said shunted wire contracting and initiating the separation of said contacts whereby to shunt said second circuit and to reduce the current in said,

winding to a value causing the armature to move away from its attracted position to accelerate the separation of said contacts.

7. A flasher switch comprising an electromagnet including a core, a winding on said core, and

an armature biased away from its attracted position, a resilient member anchored at one end thereof, a pair of opposed contacts respectively fixed to said armature and the free end of said member, a thermoresponsive wire anchored at one end and attached at the other end thereof to said member and tensioned to space said contacts, said wire being adapted upon heating to elongate and to cause said contacts to engage, said winding being adapted to be energized to move said armature to an attracted position and to move said member to a stressed position determined by said core, said wire being adapted to contract until the tension thereof is sufllcient to initiate the separation of said contacts.

8. A flasher switch comprising a base, an electromagnet on said base and including an armature resiliently biased away from its attracted position, a member anchored on said base and resiliently biased toward said armature, a pair of opposed contacts respectively mounted on said armature and said member, a thermoresponsive wire connecting said member and said base and tensioned to space said contacts, said wire being adapted upon heating to elongate until said contacts engage, said electromagnet being adapted to be energized when said contacts engage whereby said armature in its attracted position is operative to move said member to a position wherein said member is stressed and said engaged contacts are locked, said wire being adapted on cooling to contract until the tension thereof is suflicient to initiate the separation of said contacts.

9. A flasher switch comprising a base, a pair of opposed members mounted on said base and resiliently biased in the same direction, one of said members being magnetic, a pair of opposed contacts respectively mounted on said members, a thermoresponsive wire anchored to said base and attached to the other of said members and tensioned in a direction to separate said contacts, said wire being adapted to carry 8. current and to be heated and to elongate until said sen-m engage an'd thereby" shunt said wire;

electromagnetic rrieans adapted to be energizedby said current upon engagement of said confor' moving the said magnetic member towards said other member to loch saidengaged contacts, said wire being adapted on cooling'to contract and thereby allow said other member to-n'iove in a direction to initiate the separation of said contacts, saidmagnetic member being biased to move" away from said other member" to acoeleratethe separation of said contacts;

10. A flasher switch comprising a-base'; aneiectrom'agnet' includinga core, awinding on said core and an armature resiliently biased away from said core, a member anchored at one" end thereof-onsaid base and havinga portion resiliently" biased toward said armature, a pair of opposed contacts respectively mounted on said armature and member portion, a thermoresponsiwe'wire connecting said base and said member and tensioned to keep said contacts separated,

a' flr'stcircuit including said wire and a second 1-2. Irran electrie eircuit ccniprisinga lead" was a; source of electric energ rc'r energiiihfi load, flasher switch means in circuit loadand-said sources! energy; said switch mum comprising an -eleetmmagnet including a core; a winding on said core incircuit with saidload,

and armature resiliently biased away from saiii" core; a contact,- carrying" member resiliently biased" toward saidannature, a pair of" contacts respectivel mounted on said armature and said member, the'rrn'ore'sponsive rn'ean'siir ci'rcuitwith said load for tensioning said toseparste said contacts, pilot means incircuit with said source of energy; second switch means in said pilot c1r u-it, operable inrespon'seto movement or said armature and closing in the fully attracted podtion of the armature, said arm'ature being incompletely attracted with a reduction' in current passingthrough'the load whereby said second switch means is open to deene'rgme' said pil'ot means.

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